264 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.61. 



BETULA DELTOIDES, new species. 



Plate 19, fig. 3. 



Type.~C&t. No. 34,754, U.S.N.M. 



Leaf of medium size, membranaceous in texture, deltoid or trun- 

 cate-ovate in outline, perfectly truncate across nearly the whole base, 

 apex prolonged and slenderly acuminate; margin coarsely toothed, 

 the teeth very sharp, occasionlly with smaller teeth on or between 

 the larger ones ; petiole slender, one half the length of the blade ; ner- 

 vation 5-ribbed from the top of the petiole, the midrib straight, with 

 5 or 6 pairs of subopposite, craspedodrome secondaries; lowest pair 

 of secondaries or ribs at an angle of 45°, each with 4 or 5 craspedo- 

 drome tertiary branches on the outside, the lowest ones arising at the 

 top of the petiole; nerviUes fairly numerous, mainly percurreni. 



This leaf is absolutely perfect. Its length is 6 cm. and its width 

 3.5 cm., while the petiole is slightly less than 3 cm. long. The pecul- 

 iarly truncate base, sharply, obscurely doubly serrate margin and 

 5-ribbed nervation mark it exceedingly well. 



The present species if correctly allocated, makes the third made 

 known from Florissant, the others being Betulafiorissanti Lesquereux,^ 

 and Betula truncata Lesquereux.^ With the first species mentioned the 

 present one has no evident specific relationship; the other is some- 

 what nearer but differs in its much smaller size, less truncate base, a 

 different marginal dentition and above all in the nervation. 



ALNIJS PRAECORDATA Cockerell. 



Plate 19, fig. 1. 



Alnus praecordata Cockerell, Bull. Amer. Mua. Nat. Hist., vol. 24, 1908, p. 84. 

 Alnus cordata Lesquereux, Kept. U. S. Geol. Surv. Terr., vol. 8 (Cret. and Tert., 

 Fl.), 1883, p. 151. [Homonym of A. cordata Desf. 1827.] 



Tyye.—Qsii. No. 50,357, U.S.N.M. [No. 83 of Lacoe's cabinet]. 



The type and only known specimen of this species, which became 

 the property of the United States National Museum through the 

 acquisition of the Lacoe collection, is here figured for the first time. 



ALNUS, species, 

 Plate 16, fig. 2. 



Type.—Cs.t. No. 34761, U.S.N.M. 



The Hambach collection contains a single example apparently of 

 the mature strobiles of a species of Alnus. It has a very thick pedicel 

 and bears two "cones" about 1 cm. long. The form of the scales of 

 the "cones" can not be made out. 



> Lesquereux, Leo, Rept. U. 8. GeoL Surv. Terr., vol. 8 (Cret. and Tert. Fl.), 1883, p. 150, pi. 27, fig. 11. 

 2 Idem, p. 150, pi. 27, figs, 7, 8. 



